1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * Definitions for the UDP module.
8 *
9 * Version: @(#)udp.h 1.0.2 05/07/93
10 *
11 * Authors: Ross Biro
12 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
13 *
14 * Fixes:
15 * Alan Cox : Turned on udp checksums. I don't want to
16 * chase 'memory corruption' bugs that aren't!
17 */
18 #ifndef _UDP_H
19 #define _UDP_H
20
21 #include <linux/list.h>
22 #include <linux/bug.h>
23 #include <net/inet_sock.h>
24 #include <net/gso.h>
25 #include <net/sock.h>
26 #include <net/snmp.h>
27 #include <net/ip.h>
28 #include <linux/ipv6.h>
29 #include <linux/seq_file.h>
30 #include <linux/poll.h>
31 #include <linux/indirect_call_wrapper.h>
32
33 /**
34 * struct udp_skb_cb - UDP(-Lite) private variables
35 *
36 * @header: private variables used by IPv4/IPv6
37 * @cscov: checksum coverage length (UDP-Lite only)
38 * @partial_cov: if set indicates partial csum coverage
39 */
40 struct udp_skb_cb {
41 union {
42 struct inet_skb_parm h4;
43 #if IS_ENABLED(CONFIG_IPV6)
44 struct inet6_skb_parm h6;
45 #endif
46 } header;
47 __u16 cscov;
48 __u8 partial_cov;
49 };
50 #define UDP_SKB_CB(__skb) ((struct udp_skb_cb *)((__skb)->cb))
51
52 /**
53 * struct udp_hslot - UDP hash slot
54 *
55 * @head: head of list of sockets
56 * @count: number of sockets in 'head' list
57 * @lock: spinlock protecting changes to head/count
58 */
59 struct udp_hslot {
60 struct hlist_head head;
61 int count;
62 spinlock_t lock;
63 } __attribute__((aligned(2 * sizeof(long))));
64
65 /**
66 * struct udp_table - UDP table
67 *
68 * @hash: hash table, sockets are hashed on (local port)
69 * @hash2: hash table, sockets are hashed on (local port, local address)
70 * @mask: number of slots in hash tables, minus 1
71 * @log: log2(number of slots in hash table)
72 */
73 struct udp_table {
74 struct udp_hslot *hash;
75 struct udp_hslot *hash2;
76 unsigned int mask;
77 unsigned int log;
78 };
79 extern struct udp_table udp_table;
80 void udp_table_init(struct udp_table *, const char *);
81 static inline struct udp_hslot *udp_hashslot(struct udp_table *table,
82 struct net *net, unsigned int num)
83 {
84 return &table->hash[udp_hashfn(net, num, table->mask)];
85 }
86 /*
87 * For secondary hash, net_hash_mix() is performed before calling
88 * udp_hashslot2(), this explains difference with udp_hashslot()
89 */
90 static inline struct udp_hslot *udp_hashslot2(struct udp_table *table,
91 unsigned int hash)
92 {
93 return &table->hash2[hash & table->mask];
94 }
95
96 extern struct proto udp_prot;
97
98 extern atomic_long_t udp_memory_allocated;
99 DECLARE_PER_CPU(int, udp_memory_per_cpu_fw_alloc);
100
101 /* sysctl variables for udp */
102 extern long sysctl_udp_mem[3];
103 extern int sysctl_udp_rmem_min;
104 extern int sysctl_udp_wmem_min;
105
106 struct sk_buff;
107
108 /*
109 * Generic checksumming routines for UDP(-Lite) v4 and v6
110 */
111 static inline __sum16 __udp_lib_checksum_complete(struct sk_buff *skb)
112 {
113 return (UDP_SKB_CB(skb)->cscov == skb->len ?
114 __skb_checksum_complete(skb) :
115 __skb_checksum_complete_head(skb, UDP_SKB_CB(skb)->cscov));
116 }
117
118 static inline int udp_lib_checksum_complete(struct sk_buff *skb)
119 {
120 return !skb_csum_unnecessary(skb) &&
121 __udp_lib_checksum_complete(skb);
122 }
123
124 /**
125 * udp_csum_outgoing - compute UDPv4/v6 checksum over fragments
126 * @sk: socket we are writing to
127 * @skb: sk_buff containing the filled-in UDP header
128 * (checksum field must be zeroed out)
129 */
130 static inline __wsum udp_csum_outgoing(struct sock *sk, struct sk_buff *skb)
131 {
132 __wsum csum = csum_partial(skb_transport_header(skb),
133 sizeof(struct udphdr), 0);
134 skb_queue_walk(&sk->sk_write_queue, skb) {
135 csum = csum_add(csum, skb->csum);
136 }
137 return csum;
138 }
139
140 static inline __wsum udp_csum(struct sk_buff *skb)
141 {
142 __wsum csum = csum_partial(skb_transport_header(skb),
143 sizeof(struct udphdr), skb->csum);
144
145 for (skb = skb_shinfo(skb)->frag_list; skb; skb = skb->next) {
146 csum = csum_add(csum, skb->csum);
147 }
148 return csum;
149 }
150
151 static inline __sum16 udp_v4_check(int len, __be32 saddr,
152 __be32 daddr, __wsum base)
153 {
154 return csum_tcpudp_magic(saddr, daddr, len, IPPROTO_UDP, base);
155 }
156
157 void udp_set_csum(bool nocheck, struct sk_buff *skb,
158 __be32 saddr, __be32 daddr, int len);
159
160 static inline void udp_csum_pull_header(struct sk_buff *skb)
161 {
162 if (!skb->csum_valid && skb->ip_summed == CHECKSUM_NONE)
163 skb->csum = csum_partial(skb->data, sizeof(struct udphdr),
164 skb->csum);
165 skb_pull_rcsum(skb, sizeof(struct udphdr));
166 UDP_SKB_CB(skb)->cscov -= sizeof(struct udphdr);
167 }
168
169 typedef struct sock *(*udp_lookup_t)(const struct sk_buff *skb, __be16 sport,
170 __be16 dport);
171
172 void udp_v6_early_demux(struct sk_buff *skb);
173 INDIRECT_CALLABLE_DECLARE(int udpv6_rcv(struct sk_buff *));
174
175 struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
176 netdev_features_t features, bool is_ipv6);
177
178 static inline void udp_lib_init_sock(struct sock *sk)
179 {
180 struct udp_sock *up = udp_sk(sk);
181
182 skb_queue_head_init(&up->reader_queue);
183 up->forward_threshold = sk->sk_rcvbuf >> 2;
184 set_bit(SOCK_CUSTOM_SOCKOPT, &sk->sk_socket->flags);
185 }
186
187 /* hash routines shared between UDPv4/6 and UDP-Litev4/6 */
188 static inline int udp_lib_hash(struct sock *sk)
189 {
190 BUG();
191 return 0;
192 }
193
194 void udp_lib_unhash(struct sock *sk);
195 void udp_lib_rehash(struct sock *sk, u16 new_hash);
196
197 static inline void udp_lib_close(struct sock *sk, long timeout)
198 {
199 sk_common_release(sk);
200 }
201
202 int udp_lib_get_port(struct sock *sk, unsigned short snum,
203 unsigned int hash2_nulladdr);
204
205 u32 udp_flow_hashrnd(void);
206
207 static inline __be16 udp_flow_src_port(struct net *net, struct sk_buff *skb,
208 int min, int max, bool use_eth)
209 {
210 u32 hash;
211
212 if (min >= max) {
213 /* Use default range */
214 inet_get_local_port_range(net, &min, &max);
215 }
216
217 hash = skb_get_hash(skb);
218 if (unlikely(!hash)) {
219 if (use_eth) {
220 /* Can't find a normal hash, caller has indicated an
221 * Ethernet packet so use that to compute a hash.
222 */
223 hash = jhash(skb->data, 2 * ETH_ALEN,
224 (__force u32) skb->protocol);
225 } else {
226 /* Can't derive any sort of hash for the packet, set
227 * to some consistent random value.
228 */
229 hash = udp_flow_hashrnd();
230 }
231 }
232
233 /* Since this is being sent on the wire obfuscate hash a bit
234 * to minimize possbility that any useful information to an
235 * attacker is leaked. Only upper 16 bits are relevant in the
236 * computation for 16 bit port value.
237 */
238 hash ^= hash << 16;
239
240 return htons((((u64) hash * (max - min)) >> 32) + min);
241 }
242
243 static inline int udp_rqueue_get(struct sock *sk)
244 {
245 return sk_rmem_alloc_get(sk) - READ_ONCE(udp_sk(sk)->forward_deficit);
246 }
247
248 static inline bool udp_sk_bound_dev_eq(struct net *net, int bound_dev_if,
249 int dif, int sdif)
250 {
251 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
252 return inet_bound_dev_eq(!!READ_ONCE(net->ipv4.sysctl_udp_l3mdev_accept),
253 bound_dev_if, dif, sdif);
254 #else
255 return inet_bound_dev_eq(true, bound_dev_if, dif, sdif);
256 #endif
257 }
258
259 /* net/ipv4/udp.c */
260 void udp_destruct_common(struct sock *sk);
261 void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len);
262 int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb);
263 void udp_skb_destructor(struct sock *sk, struct sk_buff *skb);
264 struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags, int *off,
265 int *err);
266 static inline struct sk_buff *skb_recv_udp(struct sock *sk, unsigned int flags,
267 int *err)
268 {
269 int off = 0;
270
271 return __skb_recv_udp(sk, flags, &off, err);
272 }
273
274 int udp_v4_early_demux(struct sk_buff *skb);
275 bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst);
276 int udp_err(struct sk_buff *, u32);
277 int udp_abort(struct sock *sk, int err);
278 int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len);
279 void udp_splice_eof(struct socket *sock);
280 int udp_push_pending_frames(struct sock *sk);
281 void udp_flush_pending_frames(struct sock *sk);
282 int udp_cmsg_send(struct sock *sk, struct msghdr *msg, u16 *gso_size);
283 void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst);
284 int udp_rcv(struct sk_buff *skb);
285 int udp_ioctl(struct sock *sk, int cmd, int *karg);
286 int udp_init_sock(struct sock *sk);
287 int udp_pre_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
288 int __udp_disconnect(struct sock *sk, int flags);
289 int udp_disconnect(struct sock *sk, int flags);
290 __poll_t udp_poll(struct file *file, struct socket *sock, poll_table *wait);
291 struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
292 netdev_features_t features,
293 bool is_ipv6);
294 int udp_lib_getsockopt(struct sock *sk, int level, int optname,
295 char __user *optval, int __user *optlen);
296 int udp_lib_setsockopt(struct sock *sk, int level, int optname,
297 sockptr_t optval, unsigned int optlen,
298 int (*push_pending_frames)(struct sock *));
299 struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
300 __be32 daddr, __be16 dport, int dif);
301 struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
302 __be32 daddr, __be16 dport, int dif, int sdif,
303 struct udp_table *tbl, struct sk_buff *skb);
304 struct sock *udp4_lib_lookup_skb(const struct sk_buff *skb,
305 __be16 sport, __be16 dport);
306 struct sock *udp6_lib_lookup(struct net *net,
307 const struct in6_addr *saddr, __be16 sport,
308 const struct in6_addr *daddr, __be16 dport,
309 int dif);
310 struct sock *__udp6_lib_lookup(struct net *net,
311 const struct in6_addr *saddr, __be16 sport,
312 const struct in6_addr *daddr, __be16 dport,
313 int dif, int sdif, struct udp_table *tbl,
314 struct sk_buff *skb);
315 struct sock *udp6_lib_lookup_skb(const struct sk_buff *skb,
316 __be16 sport, __be16 dport);
317 int udp_read_skb(struct sock *sk, skb_read_actor_t recv_actor);
318
319 /* UDP uses skb->dev_scratch to cache as much information as possible and avoid
320 * possibly multiple cache miss on dequeue()
321 */
322 struct udp_dev_scratch {
323 /* skb->truesize and the stateless bit are embedded in a single field;
324 * do not use a bitfield since the compiler emits better/smaller code
325 * this way
326 */
327 u32 _tsize_state;
328
329 #if BITS_PER_LONG == 64
330 /* len and the bit needed to compute skb_csum_unnecessary
331 * will be on cold cache lines at recvmsg time.
332 * skb->len can be stored on 16 bits since the udp header has been
333 * already validated and pulled.
334 */
335 u16 len;
336 bool is_linear;
337 bool csum_unnecessary;
338 #endif
339 };
340
341 static inline struct udp_dev_scratch *udp_skb_scratch(struct sk_buff *skb)
342 {
343 return (struct udp_dev_scratch *)&skb->dev_scratch;
344 }
345
346 #if BITS_PER_LONG == 64
347 static inline unsigned int udp_skb_len(struct sk_buff *skb)
348 {
349 return udp_skb_scratch(skb)->len;
350 }
351
352 static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
353 {
354 return udp_skb_scratch(skb)->csum_unnecessary;
355 }
356
357 static inline bool udp_skb_is_linear(struct sk_buff *skb)
358 {
359 return udp_skb_scratch(skb)->is_linear;
360 }
361
362 #else
363 static inline unsigned int udp_skb_len(struct sk_buff *skb)
364 {
365 return skb->len;
366 }
367
368 static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
369 {
370 return skb_csum_unnecessary(skb);
371 }
372
373 static inline bool udp_skb_is_linear(struct sk_buff *skb)
374 {
375 return !skb_is_nonlinear(skb);
376 }
377 #endif
378
379 static inline int copy_linear_skb(struct sk_buff *skb, int len, int off,
380 struct iov_iter *to)
381 {
382 return copy_to_iter_full(skb->data + off, len, to) ? 0 : -EFAULT;
383 }
384
385 /*
386 * SNMP statistics for UDP and UDP-Lite
387 */
388 #define UDP_INC_STATS(net, field, is_udplite) do { \
389 if (is_udplite) SNMP_INC_STATS((net)->mib.udplite_statistics, field); \
390 else SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0)
391 #define __UDP_INC_STATS(net, field, is_udplite) do { \
392 if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_statistics, field); \
393 else __SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0)
394
395 #define __UDP6_INC_STATS(net, field, is_udplite) do { \
396 if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_stats_in6, field);\
397 else __SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \
398 } while(0)
399 #define UDP6_INC_STATS(net, field, __lite) do { \
400 if (__lite) SNMP_INC_STATS((net)->mib.udplite_stats_in6, field); \
401 else SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \
402 } while(0)
403
404 #if IS_ENABLED(CONFIG_IPV6)
405 #define __UDPX_MIB(sk, ipv4) \
406 ({ \
407 ipv4 ? (IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics : \
408 sock_net(sk)->mib.udp_statistics) : \
409 (IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_stats_in6 : \
410 sock_net(sk)->mib.udp_stats_in6); \
411 })
412 #else
413 #define __UDPX_MIB(sk, ipv4) \
414 ({ \
415 IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics : \
416 sock_net(sk)->mib.udp_statistics; \
417 })
418 #endif
419
420 #define __UDPX_INC_STATS(sk, field) \
421 __SNMP_INC_STATS(__UDPX_MIB(sk, (sk)->sk_family == AF_INET), field)
422
423 #ifdef CONFIG_PROC_FS
424 struct udp_seq_afinfo {
425 sa_family_t family;
426 struct udp_table *udp_table;
427 };
428
429 struct udp_iter_state {
430 struct seq_net_private p;
431 int bucket;
432 };
433
434 void *udp_seq_start(struct seq_file *seq, loff_t *pos);
435 void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos);
436 void udp_seq_stop(struct seq_file *seq, void *v);
437
438 extern const struct seq_operations udp_seq_ops;
439 extern const struct seq_operations udp6_seq_ops;
440
441 int udp4_proc_init(void);
442 void udp4_proc_exit(void);
443 #endif /* CONFIG_PROC_FS */
444
445 int udpv4_offload_init(void);
446
447 void udp_init(void);
448
449 DECLARE_STATIC_KEY_FALSE(udp_encap_needed_key);
450 void udp_encap_enable(void);
451 void udp_encap_disable(void);
452 #if IS_ENABLED(CONFIG_IPV6)
453 DECLARE_STATIC_KEY_FALSE(udpv6_encap_needed_key);
454 void udpv6_encap_enable(void);
455 #endif
456
457 static inline struct sk_buff *udp_rcv_segment(struct sock *sk,
458 struct sk_buff *skb, bool ipv4)
459 {
460 netdev_features_t features = NETIF_F_SG;
461 struct sk_buff *segs;
462
463 /* Avoid csum recalculation by skb_segment unless userspace explicitly
464 * asks for the final checksum values
465 */
466 if (!inet_get_convert_csum(sk))
467 features |= NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM;
468
469 /* UDP segmentation expects packets of type CHECKSUM_PARTIAL or
470 * CHECKSUM_NONE in __udp_gso_segment. UDP GRO indeed builds partial
471 * packets in udp_gro_complete_segment. As does UDP GSO, verified by
472 * udp_send_skb. But when those packets are looped in dev_loopback_xmit
473 * their ip_summed CHECKSUM_NONE is changed to CHECKSUM_UNNECESSARY.
474 * Reset in this specific case, where PARTIAL is both correct and
475 * required.
476 */
477 if (skb->pkt_type == PACKET_LOOPBACK)
478 skb->ip_summed = CHECKSUM_PARTIAL;
479
480 /* the GSO CB lays after the UDP one, no need to save and restore any
481 * CB fragment
482 */
483 segs = __skb_gso_segment(skb, features, false);
484 if (IS_ERR_OR_NULL(segs)) {
485 int segs_nr = skb_shinfo(skb)->gso_segs;
486
487 atomic_add(segs_nr, &sk->sk_drops);
488 SNMP_ADD_STATS(__UDPX_MIB(sk, ipv4), UDP_MIB_INERRORS, segs_nr);
489 kfree_skb(skb);
490 return NULL;
491 }
492
493 consume_skb(skb);
494 return segs;
495 }
496
497 static inline void udp_post_segment_fix_csum(struct sk_buff *skb)
498 {
499 /* UDP-lite can't land here - no GRO */
500 WARN_ON_ONCE(UDP_SKB_CB(skb)->partial_cov);
501
502 /* UDP packets generated with UDP_SEGMENT and traversing:
503 *
504 * UDP tunnel(xmit) -> veth (segmentation) -> veth (gro) -> UDP tunnel (rx)
505 *
506 * can reach an UDP socket with CHECKSUM_NONE, because
507 * __iptunnel_pull_header() converts CHECKSUM_PARTIAL into NONE.
508 * SKB_GSO_UDP_L4 or SKB_GSO_FRAGLIST packets with no UDP tunnel will
509 * have a valid checksum, as the GRO engine validates the UDP csum
510 * before the aggregation and nobody strips such info in between.
511 * Instead of adding another check in the tunnel fastpath, we can force
512 * a valid csum after the segmentation.
513 * Additionally fixup the UDP CB.
514 */
515 UDP_SKB_CB(skb)->cscov = skb->len;
516 if (skb->ip_summed == CHECKSUM_NONE && !skb->csum_valid)
517 skb->csum_valid = 1;
518 }
519
520 #ifdef CONFIG_BPF_SYSCALL
521 struct sk_psock;
522 int udp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore);
523 #endif
524
525 #endif /* _UDP_H */
526
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